PDF《热处理后水稻土溶解性有机质光谱特征的变化》

摘要: 土壤溶解性有机质 (DOM) 由胡敏酸、 富里酸等组成.

为了解热处理对土壤 DOM 的结构和组分的影响, 将水稻土样品在温 度200 益、

250 益、

300 益和时间

2、

4、

6 h 下进行加热, 对热处理前后的水稻土 DOM 进行了紫外光谱、 三维荧光和红外光谱分析.结 果表明, 对于紫外-可见光光谱的特征指标

250 nm 和365 nm 紫外吸光度比值 E2/E3, 随着加热温度增加而逐渐增加, 而单位溶解性 有机碳浓度下

254、

260、

280 nm 处波长 SUVA

254、 SUVA260 和SUVA280 则逐渐减少,表明随着加热温度增加, DOM 的芳香性和疏水性 降低;

加热后 DOM 在253 nm 与203 nm 吸光度的比值 A253/A203 由低到高, 表明未加热时 DOM 组分芳香环取代基以脂肪链为主, 加 热后脂肪类物质大量分解. 样品加热后的三维荧光光谱发生蓝移现象, 荧光强度增加, 同时紫外区类富里酸荧光峰值与可见区类富 里酸荧光峰值的比值 r (A/C) 降低, 表明加热后土壤 DOM 芳香性降低, 分子量降低.红外光谱特征表明, 加热后 DOM 中羧酸类物质 增多;

200 益和

250 益加热时, DOM 中脂肪族类物质增加,

300 益加热时脂肪族类物质减少. 关键词: 溶解性有机物;

热处理;

腐殖程度;

水稻土;

光谱特征 中图分类号: X53 文献标志码: A 文章编号: 1672-2043 (2018) 03-0505-10 doi:10.11654/jaes.2017-1026 Changes in the spectral characteristics of dissolved organic matter from paddy soil after heating PANG Yan-hua1 , CHEN Li-na1,2 , ZHANG Sheng1 , TU Bao-hua1 , ZHANG Wen-yi1 , HUANG Zhao-qin3 , HU Lin-chao1,2* (1.School of Environmental &

Safety Engineering, Changzhou University, Changzhou 213164, China;

2.Changzhou Academy of Environmen原tal Science, Changzhou 213022, China;

3.College of Environmental and Ecologic, Jiangsu Open University, Nanjing 210036, China) Abstract: Dissolved organic matter (DOM)is an important soil component. It consists of low-molecular-weight free amino acids, carbohy原drates, organic acids, and high-molecular-weight enzymes, amino sugars, humus, and so on. It plays an important role in many chemical and biological processes in the soil. In this study, UV-VIS spectra, three-dimensional fluorescence, and infrared spectroscopy were used to ana原lyze the effect of heat treatment on the structure and composition of DOM in different soils. The paddy soil samples were heated at

200 益,

250 益, and

300 益for

2 h,

4 h, and

6 h, respectively. SUVA254, SUVA260, and SUVA280 were the absorption coefficients for unit dissolved or原ganic carbon concentrations at 254, 260, and

280 nm, respectively. The results showed that the ultraviolet absorbance ratio (E2/E3 )increased and the SUVA254, SUVA260, and SUVA280 values decreased when the temperature rose. They also indicated that the DOM aromaticity and hy原drophobicity decreased when the temperature increased. Furthermore, the A253/A203 absorbance ratio increased when the temperature rose. This indicated that the aromatic ring substituents of the DOM component were mainly aliphatic chains when unheated and that the fatty sub原stances were decomposed in large quantities when heated. The three-dimensional fluorescence spectra showed that a blue-shift in the main fluorescence peak appeared and fluorescence intensity increased. The ratio of the fluorescence peak value of fulvic acid in the ultraviolet re原 收稿日期: 圆园17原07原24 录用日期: 圆园17原12原19 作者简介: 庞燕华 (1992―) , 男, 江苏启东人, 硕士研究生, 从事土壤修复研究.E-mail: 863383065@ qq.com * 通信作者: 胡林潮 E-mail: [email protected] 基金项目: 国家自然科学基金项目 (41403095) ;